Dave,
If you are reusing the telrex elements for part of this you will want to put
your build into a mech anal program like Yagi Mechanical or similar and
check out the wind survivability. The 40m 3-element Telrex for example
comes out to show a failure at around 53 mph and that's assuming they are
using 6061 which is not at all a known fact. I'm reusing a 40m telrex boom
and 20m Telrex aluminum for a 17m beam and the numbers come out pretty good
there - assuming 6061. Wind is a big problem here - it may or may not be on
your end.
Good luck.
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: Dave Sublette
Sent: Thursday, July 27, 2017 7:28 AM
To: Central KY CW/DX Operators ; Bill via TowerTalk
Subject: [TowerTalk] Modeling the Moxon
I have spent a fair amount of time reading a few of the Moxon construction
articles about the modified Moxon for 40 meters. I have a spare 6 element
20 meter Telrex monobander for 20 meters in my barn. Doing some scratching
on paper, it looks like I could build two, two element Moxons for 40 using
the material in that yagi. I would need to buy the tubing necessary to
build the Tee sections on the end.
Since all of the element diameters and taper schedules would be different, I
should model it. I have the Antenna Model Software package. I haven’t used
it much. I haven’t modeled antennas in over 15 years. I used to use K6STI
software when I did and I loved it. Some of the articles I have read say
good things about the Antenna Model program. I am wondering if that would
be good enough to use on the Moxon.
Now I know the Moxon doesn’t model well. The W6NL version is the standard
and the best advice is to build it like that. But I have all this beautiful
aluminum that I don’t want to waste. Plus, the 3 1/2 inch boom on the T-rex
is really stout enough to handle this antenna. At least one article says
they wish they had used a larger boom diameter.
I suppose a good plan would be to model the W6NL and then my version on the
same software and adjust my version until the results matched those obtained
with the W6NL. The question is .. Is the Antenna Model package adequate
for the job?
A really good answer would be that someone has already modeled the W6NL on
Antenna Model and would share the file with me. :-)
Thanks,
Dave, K4TO
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